Rotational-flow spray nozzle and process of using same

ABSTRACT

A solder-flux composition is sprayed onto a substrate by rotating the solder-flux composition inside a spray cap, and before the solder-flux liquid exits the spray cap, perturbing the flow thereof with a fluid.

TECHNICAL FIELD

Embodiments relate generally to integrated circuit devices. Inparticular, embodiments relate to processes of applying a solder flux toa substrate.

TECHNICAL BACKGROUND

Processors and other integrated circuit chips can generate significantheat. During miniaturization efforts, not only are circuits beingcrowded into smaller geometries, but also multiple chips are beingcrowded into smaller packages. Flip-chip configurations are affected bythe miniaturization because mounting space is also shrinking.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to depict the manner in which the embodiments are obtained, amore particular description of embodiments briefly described above willbe rendered by reference to exemplary embodiments that are illustratedin the appended drawings. Understanding that these drawings depict onlytypical embodiments that are not necessarily drawn to scale and are nottherefore to be considered to be limiting of its scope, the embodimentswill be described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 is a cross-section elevation of a spray nozzle during a processof coating according to an embodiment;

FIG. 2 is a cross-section elevation of a spray nozzle during a processof coating according to an embodiment;

FIGS. 3A, 3B, and 3C are time-progressive depictions of a detail section3 taken from FIG. 2;

FIG. 4 is a cross-section elevation of a spray apparatus during aprocess of coating according to an embodiment;

FIG. 5 is a cross-section elevation of a spray apparatus 500 during aprocess of coating according to an embodiment;

FIG. 6A is a cross-section elevation of a integrated circuit packageduring solder flux processing according to an embodiment;

FIG. 6B is a cross-section elevation of the integrated circuit packagedepicted in FIG. 6A after further processing;

FIG. 6C is a cross-section elevation of the integrated circuit packagedepicted in FIG. 6B after further processing; and

FIG. 7 is a flow chart 700 that describes process flow embodiments.

DETAILED DESCRIPTION

The present disclosure relates to spray processing of films such assolder flux films on bond pads.

The following description includes terms, such as upper, lower, first,second, etc. that are used for descriptive purposes only and are not tobe construed as limiting. The embodiments of an apparatus or articledescribed herein can be manufactured, used, or shipped in a number ofpositions and orientations. The terms “die” and “chip” generally referto the physical object that is the basic workpiece that is transformedby various process operations into the desired integrated circuitdevice. A die is usually singulated from a wafer, and wafers may be madeof semiconducting, non-semiconducting, or combinations of semiconductingand non-semiconducting materials. A board is typically aresin-impregnated fiberglass structure that acts as a mounting substratefor the die. A heat spreader in this disclosure is a thin structure thatis dual-die-and-dual-heat spreader processed.

Reference will now be made to the drawings wherein like structures willbe provided with like reference designations. In order to show thestructures of embodiments most clearly, the drawings included herein arediagrammatic representations of various embodiments. Thus, the actualappearance of the fabricated structures, for example in aphotomicrograph, may appear different while still incorporating thestructures of embodiments. Moreover, the drawings show only thestructures useful to understand the embodiments. Additional structuresknown in the art have not been included to maintain the clarity of thedrawings.

FIG. 1 is a cross-section elevation of a spray apparatus 100 during aprocess of coating according to an embodiment. The spray apparatus 100includes a coaxial fluid-flow cap 110 that is configured about alongitudinal symmetry line 108. A solder flux liquid inlet tube 112 isdisposed within the coaxial fluid-flow cap 110. A rotatable firstfitting 114 allows the solder flux liquid inlet tube 112 to be rotatablycoupled to the coaxial fluid-flow cap 110 according to an embodiment. Asolder flux liquid supply conduit 116 is coupled to the rotatable firstfitting 114 and to a rotatable second fitting 118. The rotatable secondfitting 118 is further coupled to a solder flux liquid source 120.

In an embodiment, the coaxial fluid-flow cap 110 and the solder fluxliquid inlet tube 112 rotate together, such that the first fitting 114is not rotatable, but the second fitting is rotatable. In thisembodiment, there is one moving coupling.

A fluid flow 106 is also used in FIG. 1 within the regions of thecoaxial fluid-flow cap 110 that is outside the solder flux liquid inlettube 112. The general direction of fluid flow 106 is toward the mouth122 of the solder flux liquid inlet tube 112 as influenced by the shapeof the coaxial fluid-flow cap 110.

As the solder flux liquid inlet tube 112 rotates and solder flux liquidreaches the mouth 122, the solder flux liquid shears into primaryfragments 127, and away from the solder flux liquid inlet tube 112 underthe centrifugal force that the rotating motion of the solder flux liquidinlet tube 112 imposes upon it. Simultaneously, the fluid flow 106perturbs the primary fragments 127 of the solder flux liquid and therebycauses the primary fragments 127 to further fragment into secondaryfragments 128.

The coaxial fluid-flow cap 110 includes a nozzle 130 through which thesecondary fragments 128 must pass. As the secondary fragments 128 of thesolder flux liquid exit the nozzle 130, they experience a pressurechange and become tertiary fragments 129.

Control of the size of the various fragments 127, 128, and 129 can bedone by various methods in FIG. 1. The rate of flow of the solder fluxliquid through the solder flux liquid inlet tube 112 is one factor,coupled with the rate of rotation of the solder flux liquid inlet tube112 that will affect the size of the primary fragments 127. The tip oropening size, the geometry of opening—circular or oval cross-sectionalso affects the size of the fragments prior to influence by coaxialair. In an embodiment, the shape of the mouth 122 is circular. In anembodiment, the shape of the mouth 122 is rectangular such as a square.In an embodiment, the shape of the mouth 122 is eccentric such as anoval. In an embodiment, the shape of the mouth 122 is a combination ofrectilinear and curvilinear, such as a star shape with rounded points.In an embodiment, the process wherein a high viscosity flux from 0 to1000 cp is sheared by rotational motion using coaxial assist through aconcentrically rotating cap to limit overspray and aid tighter fluxcoverage.

The viscosity of the solder flux liquid within the solder flux liquidinlet tube 112 will also act in concert with the rate of flow and therate of rotation to affect the size of the primary fragments 127.

The quality of the fluid in the fluid flow 106 will also affect thefragmentation of the primary fragments 127. In an embodiment, the fluidin the fluid flow 106 is itself a liquid in an atomized state. In anembodiment, the fluid in the fluid flow 106 is a vapor that behaves likea saturated gas. In an embodiment, the fluid in the fluid flow 106 is agas. The fluid flow 106 can be referred to as an “air assist,” but thisterm is intended to be an abbreviation of the various fluid flows 106that have been described. Additionally, when the fluid flow 106 is agas, it can be a gas that is unreactive to the system of the solder fluxliquid.

The exact spacing 132 between the mouth 122 of the solder flux liquidinlet tube 112 and the nozzle 130 is also a factor that affects the sizeof the secondary fragments 128. The fluid flow 106 has a principaleffect upon the primary fragments 127 in this spacing 132. In anembodiment for dimensional analysis, the mouth 122 has a diameter ofunity, and the opening of the nozzle 130 has a diameter in a range fromabout unity to about 10 times unity. In an embodiment, the mouth 122 hasthe diameter of unity, and the spacing 132 between the mouth 122 and thenozzle 130 is in a range from about 0.1 times unity to about five timesunity. In an embodiment, the spacing 132 between the mouth 122 and thenozzle 130 is about 2 mm.

In an embodiment, the mouth 122 has a diameter of unity, the opening ofthe nozzle 130 has a diameter of about five times unity, and the spacing132 between the mouth 122 and the nozzle 130 is about three times unity.

In an embodiment, the angle 134 that is placed at the mouth 122 of thesolder flux liquid inlet tube 112 creates a backpressure within thesolder flux liquid, which acts in antagonism to the shear force that isbeing directed at the primary fragments 127. Rotational directions aredepicted at items 124 and 126. The angle 134 therefore affects theformation of the primary fragments 127. In an embodiment, the angle 134is in a range from about 1° to about 90° deviation from the vertical. Inan embodiment, the angle 134 is about 30° deviation from the vertical.In an embodiment, no angle is formed at the mouth 122 of the solder fluxliquid inlet tube 112.

The tertiary fragments 129 are depicted as six streams that are beingdriven away from the nozzle 130 and toward a substrate 136 that includesa bond pad 138. The tertiary fragments 129 of the solder flux liquidimpinge on the bond pad 138 by X-Y placement control of the soldercoaxial fluid-flow cap 110. Two keep-out zones (KOZs) 140 and 142represent locations on the substrate 136 that are not to besignificantly contacted with the tertiary fragments 129 of the solderflux liquid.

As the tertiary fragments 129 of the solder flux liquid impinge on thebond pad 138, there is inherent splashing that depends upon the size ofthe tertiary fragments 129, the velocity, the wetting affinity for thebond pad 138, and the viscosity of the tertiary fragments 129, amongothers.

FIG. 2 is a cross-section elevation of a spray apparatus 200 during aprocess of coating according to an embodiment. The spray apparatus 200includes a coaxial fluid-flow cap 210 that is configured about alongitudinal symmetry line 208. A solder flux liquid inlet tube 212 isdisposed within the coaxial fluid-flow cap 210. A rotatable firstfitting 214 allows the solder flux liquid inlet tube 212 to be rotatablycoupled to the coaxial fluid-flow cap 210 according to an embodiment. Asolder flux liquid supply conduit 216 is coupled to the rotatable firstfitting 214 and to a rotatable second fitting 218. The rotatable secondfitting 218 is further coupled to a solder flux liquid source 220.

In an embodiment, the coaxial fluid-flow cap 210 and the solder fluxliquid inlet tube 212 rotate together, such that the first fitting 214is not rotatable, but the second fitting 218 is rotatable. In thisembodiment, there is one moving coupling.

A fluid flow 206 is also used in FIG. 2 within the regions of thecoaxial fluid-flow cap 210 that is outside the solder flux liquid inlettube 212. The general direction of fluid flow 206 is toward the mouth222 of the solder flux liquid inlet tube 212. The initial direction ofthe fluid flow 206 is a helical flow stream that originates in a bushingreservoir 244, and that passes into the fluid-flow cap 210 at afluid-injection port that is a cap-tangent orifice 246. The generaldirection of the fluid flow 206 is also influenced by the shape of thecoaxial fluid-flow cap 210.

As the solder flux liquid inlet tube 212 rotates and solder flux liquidreaches the mouth 222, the solder flux liquid shears into primaryfragments 227, and away from the solder flux liquid inlet tube 212 underthe centrifugal force that the rotating motion of the solder flux liquidinlet tube 212 imposes upon it. Simultaneously, the fluid flow 206 as an“air assist,” perturbs the primary fragments 227 of the solder fluxliquid and thereby causes the primary fragments 227 to further fragmentinto secondary fragments 228.

In an embodiment, the coaxial fluid-flow cap 210 includes a nozzlesimilar to the nozzle 130 depicted in FIG. 1. Control of the size of thevarious fragments 227, 228, and 229 can be done by the various methodsthat are described with respect to the apparatus depicted in FIG. 1.

The exact spacing 232 between the mouth 222 of the solder flux liquidinlet tube 212 and the nozzle 230 is also a factor that affects the sizeof the secondary fragments 228. The tertiary fragments 229 are depictedas six streams that are being driven away from the nozzle 230 and towarda substrate 236 that includes a bond pad 238. The tertiary fragments 229of the solder flux liquid impinge on the bond pad 238 by X-Y placementcontrol of the solder coaxial fluid-flow cap 210. Two keep-out zones(KOZs) 240 and 242 represent locations on the substrate 236 that are notto be significantly contacted with the tertiary fragments 229 of thesolder flux liquid. Rotational directions are depicted at items 224 and226.

As the tertiary fragments 229 of the solder flux liquid impinge on thebond pad 238, there is inherent splashing that depends upon the size ofthe tertiary fragments 229, the velocity, the wetting affinity for thebond pad 238, and the viscosity of the tertiary fragments 229, amongothers.

FIGS. 3A, 3B, and 3C are time-progressive depictions of a detail section3 taken from FIG. 2. The depiction in FIGS. 3A, 3B, and 3C aresimplified by assuming a streamlined flow of an air-assist fluid. Theflow regime can be more complex, such as a turbulent flow of theair-assist fluid, that perturbs the primary fragments.

In FIG. 3A, a primary fragment 227 has exited the solder flux liquidinlet tube 212 (FIG. 2) and is falling away as illustrated by the firstvector 348. The first vector 348 represents the effect of thecentrifugal force upon the primary fragment 227, as well as the effectof gravity thereupon, if the process is being carried out in a G-field.A second vector 350 represents the flow regime of the fluid flow 206 asit causes a shearing force upon the primary fragment 227. In FIG. 3B,the second vector causes a perturbation upon the integrity of primaryfragment 227. The perturbation is represented by the primary fragment227 beginning to separate into more than one smaller fragments. In FIG.3C, the second vector 350 has accomplished a further dividing of theprimary fragment 227 into a plurality of secondary fragments 228.Splashing of the secondary fragments 228 is less likely than that of theprimary fragments 227, where all other factors are considered equal orless significant.

FIG. 4 is a cross-section elevation of a spray apparatus 400 during aprocess of coating according to an embodiment. The spray apparatus 400includes a coaxial fluid-flow cap 410 that is configured about alongitudinal symmetry line 408. A solder flux liquid inlet tube 412 isdisposed within the coaxial fluid-flow cap 410. A rotatable firstfitting 414 allows the solder flux liquid inlet tube 412 to be rotatablycoupled to the coaxial fluid-flow cap 410 according to an embodiment. Asolder flux liquid supply conduit 416 is coupled to the rotatable firstfitting 414 and to a rotatable second fitting 418. The rotatable secondfitting 418 is further coupled to a solder flux liquid source 420.Rotational directions are depicted at items 424 and 426.

In an embodiment, the coaxial fluid-flow cap 410 and the solder fluxliquid inlet tube 412 rotate together, such that the first fitting 414is not rotatable but the second fitting 418 is rotatable. In thisembodiment, there is one moving coupling.

A fluid flow 406 is also used in FIG. 4 within the regions of thecoaxial fluid-flow cap 410 that is outside the solder flux liquid inlettube 412. The general direction of fluid flow 406 is toward the mouth422 of the solder flux liquid inlet tube 412. The initial direction ofthe fluid flow 406 is a substantially downward vertical flow stream thatoriginates in a bushing reservoir 452 and that passes into thefluid-flow cap 410 at a fluid-injection port that is a cap-coaxialorifice 446. The general direction of the fluid flow 406 is alsoinfluenced by the shape of the coaxial fluid-flow cap 410.

Where the process is conducted in a gravity environment and assuming theorientation of the 400 is a illustrated in FIG. 4, the secondaryfragments 428 will have a downward vertical component in the firstvector (see FIG. 3A). Nevertheless, the flow regime depicted in FIG. 4for the fluid flow 406 can be qualified as an “orthogonal perturbation”of the primary fragments. In any event, the quality of the primaryfragments are affected by second perturbation of the flow regime fromthe fluid flow 406. In some embodiments, the perturbation is asubstantially orthogonal perturbation. In some embodiments, theperturbation is a nominally contrary to the first vector (see 248 inFIG. 3A). In an embodiment, the second perturbation is even collinear,but the second vector is different in quantity from the first vector.

In an embodiment, the coaxial fluid-flow cap 410 includes a nozzlesimilar to the nozzle 130 depicted in FIG. 1. Control of the size of thevarious fragments 427, 428, and 429 can be done by the various methodsthat are described with respect to the apparatus depicted in FIG. 1 andin FIG. 2. As flow of the solder flux liquid develops near the mouth422, upstream solder flux liquid changes from a plug- or slug flowregime 423, to a transition regime 425, and then to the first fragments427.

The exact spacing 432 between the mouth 422 of the solder flux liquidinlet tube 412 and the nozzle 430 is also a factor that affects the sizeof the secondary fragments 428. The tertiary fragments 429 are depictedas six streams that are being driven away from the nozzle 430, andtoward a substrate 436 that includes a bond pad 438. The tertiaryfragments 429 of the solder flux liquid impinge on the bond pad 438 byX-Y placement control of the solder coaxial fluid-flow cap 410. Two KOZs440 and 442 represent locations on the substrate 436 that are not to besignificantly contacted with the tertiary fragments 429 of the solderflux liquid.

FIG. 5 is a cross-section elevation of a spray apparatus 500 during aprocess of coating according to an embodiment. The spray apparatus 500includes a coaxial fluid-flow cap 510 that is configured about alongitudinal symmetry line 508. The structures depicted in FIG. 5 aresubstantially similar to the structures depicted in FIG. 4.Consequently, the reference numbers are mostly retained. Rotation of thecoaxial fluid-flow cap 510 is depicted to be counterclockwise, whilerotation of the solder flux liquid inlet tube 512 is depicted to beclockwise. This counter-rotation of the two structures 510 and 512represents another processing factor that can affect the size of thesecondary fragments 528, and consequently, the tertiary fragments 529.In other words, the counter-rotation represents independently rotatablestructures between the coaxial fluid-flow cap 510 and the solder fluxliquid inlet tube 512. Independently rotatable can mean rotating in thesame or opposite directions, but in either cases, not necessarily withthe same angular velocity.

FIG. 6A is a cross-section elevation of a integrated circuit package 600during solder flux processing according to an embodiment. An integratedcircuit (IC) die 610 is flip-chip disposed above a mounting substrate612 and is to be electrically coupled to the mounting substrate 612through a series of electrical bumps, one of which is indicated with thereference numeral 614.

A solder flux composition 616 is depicted as having been deposited uponthe mounting substrate 612. The solder flux composition 616 has wetted abond pad 618 that is disposed on the upper surface 620 of the mountingsubstrate 612. Depositing of the solder flux composition 616 is done byX-Y grid spraying according to an embodiment.

FIG. 6B is a cross-section elevation of the integrated circuit packagedepicted in FIG. 6A after further processing. The IC package 601 depictsreflow of the solder bump 614, such that it is reflowing without thesolder drawing too far from the bond pad 618 from a KOZ 622 toward asecond KOZ 624. The KOZs are regions that must remain clear of solderflux materials for further packaging needs and that also would createpossible solder-wick opens (SWOs) if the solder is allowed to flow intothese zones. The KOZ in this case is to be defined as the perimeterenclosing the entire bond-pad array.

FIG. 6C is a cross-section elevation of the integrated circuit packagedepicted in FIG. 6B after further processing. The IC package 602 depictsa post flux-removal condition. In an embodiment, a liquid is used towash any residual flux from the region of the reflowed solder bump 615.

FIG. 6C also depicts further processing of the IC package 602 such thatthe IC die 610 has been reflow mounted to the mounting substrate 612.The IC die 610 therefore makes electrical communication to the mountingsubstrate 612 though the solder bumps 615 FIG. 7 is a flow chart 700that describes process flow embodiments.

At 710, the process includes contacting a solder flux composition to amounting substrate under conditions of a first shear force upon thesolder flux liquid and a second perturbation force by an air-assistliquid. In an embodiment, the process commences and terminates at 710.

At 720, the process includes heating the solder flux composition to thereflow temperature of the solder bump. In an embodiment, the methodcommences at 710 and terminates at 720. In an embodiment, the processcommences and terminates at 720.

At 730, the process includes washing the package to remove residualsolder flux. In an embodiment, the method commences at 710 andterminates at 730.

At 740, the package is installed into a computing system.

Various solder fluxes can be used in the process embodiments. In variousembodiments, the solder flux composition may be used as part of asoldering process for forming various integrated circuit devices. Forthe embodiments, a solder flux composition embodiment may remove oxidefrom a surface onto which soldering is to occur, thereby increasing theability of the solder to adhere to the surface of the substrate. In someembodiments, the solder flux composition embodiment may prevent oxidegrowth on a surface to be soldered as well as decreasing air and/orcontaminants at the surface of the substrate.

In an embodiment, a solder flux composition includes tartaric acid. Agroup of solder flux compositions include the tartaric acid, a resin, anamine, a solvent, and the solution, reaction, and mixture productsthereof. The tartaric acid-containing solder flux composition can beobtained from Senju America, Inc. of Great Neck, N.Y. One selectedsolder flux composition from Senju is Senju 42™.

Where a surfactant is used, sometimes referred to as a flow modifier,the specific surfactant that is employed depends upon compatibility withthe solder flux composition. In an embodiment, the surfactant is anionicsuch as long chain alkyl carboxylic acids, such as lauric acids, stericacids, and the like. In an embodiment, the surfactant is nonionic.Examples of nonionic surfactants are polyethylene oxides, poly propyleneoxides, and the like. In an embodiment, the surfactant is cationic, suchas alkyl ammonium salts, such as tert butyl ammonium chlorides, orhydroxides. In an embodiment, the flow modifier is provided in a rangefrom about 0.1% to about 10% by weight of the total solder fluxcomposition when it is prepared.

In some embodiments, an amine is used. In an embodiment, the amine is analkyl substituted amine. In an embodiment, the amine is an ethanolamine. In an embodiment, the amine is an ethoxylated amine. In anembodiment, the amine is a propoxylated amine.

In an embodiment, a liquid primary aromatic diamine is used. One exampleliquid primary aromatic diamine is diethyldiaminotoluene (DETDA), whichis marketed as ETHACURE® 100 from Ethyl Corporation of Richmond, Va.Another example liquid primary aromatic diamine is adithiomethyldiaminotoluene such as Ethacure® 300. Another example liquidprimary aromatic diamine is an alkylated methylenedianiline such asLapox® K-450 manufactured by Royce International of Jericho, N.Y.

In an embodiment, a liquid hindered primary aliphatic amine is used. Oneexample liquid hindered primary aliphatic amine is an isophoronediamine. Another example liquid hindered primary aliphatic amine is analkylated methylenedianiline such as Ancamine® 2049 manufactured byPacific Anchor Chemical Corporation of Allentown, Pa.

In an embodiment, a liquid secondary aromatic amine is used. One exampleliquid secondary aromatic amine embodiment is an N,N′-dialkylphenylenediamine such as Unilink® 4100 manufactured by DorfKetal of Stafford,Tex. Another example liquid secondary aromatic amine embodiment is anN,N′-dialkylmethylenedianilines: i.e. Unilink® 4200.

In various embodiments, a solder flux composition may comprise less than40 weight % of the amine.

In an embodiment, a resin is used to provide tackiness of the solderflux composition to the bond pad and the solder bump up to and includingthe time of reflow. The solder flux composition may include the resin,which may be present in an amount from about 1% to about 20% by weightbased on the organic components present.

In an embodiment, a cycloaliphatic epoxy resin is used. In anembodiment, a bisphenol A type epoxy resin is used. In an embodiment, abisphenol-F type epoxy resin is used. In an embodiment, a novolac epoxyresin is used. In an embodiment, a biphenyl type epoxy resin is used. Inan embodiment, a naphthalene type epoxy resin is used. In an embodiment,a dicyclopentadiene-phenol type epoxy resin is used. In an embodiment, acombination of any two of the resins is used. In an embodiment, acombination of any three of the resins is used. In an embodiment, acombination of any four of the resins is used.

This Detailed Description refers to the accompanying drawings that show,by way of illustration, specific aspects and embodiments in which thepresent disclosure may be practiced. These embodiments are described insufficient detail to enable those skilled in the art to practice thedisclosed embodiments. Other embodiments may be used and structural,logical, and electrical changes may be made without departing from thescope of the present disclosure. The various embodiments are notnecessarily mutually exclusive, as some embodiments can be combined withone or more other embodiments to form new embodiments.

The term “horizontal” as used in this document is defined as a planeparallel to the conventional plane or surface of a wafer or substrate,regardless of the orientation of the wafer or substrate. The term“vertical” refers to a direction perpendicular to the horizontal asdefined above. Prepositions, such as “on”, “side” (as in “sidewall”),“higher”, “lower”, “over”, and “under” are defined with respect to theconventional plane or surface being on the top surface of the wafer orsubstrate, regardless of the orientation of the wafer or substrate. TheDetailed Description is, therefore, not to be taken in a limiting sense,and the scope of this disclosure is defined only by the appended claims,along with the full scope of equivalents to which such claims areentitled.

The Abstract is provided to comply with 37 C.F.R. §1.72(b) requiring anabstract that will allow the reader to quickly ascertain the nature andgist of the technical disclosure. It is submitted with the understandingthat it will not be used to interpret or limit the scope or meaning ofthe claims.

In the foregoing Detailed Description, various features are groupedtogether in a single embodiment for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments of the inventionrequire more features than are expressly recited in each claim. Rather,as the following claims reflect, inventive subject matter lies in lessthan all features of a single disclosed embodiment. Thus the followingclaims are hereby incorporated into the Detailed Description, with eachclaim standing on its own as a separate embodiment.

It will be readily understood to those skilled in the art that variousother changes in the details, material, and arrangements of the partsand method stages that have been described and illustrated to explainthe nature of this invention may be made without departing from theprinciples and scope of the invention as expressed in the subjoinedclaims.

1. A process comprising: injecting a solder flux liquid into a coaxialfluid-flow cap through a solder flux liquid inlet tube; in the coaxialfluid-flow cap, causing the solder flux liquid to achieve a rotationalflow motion; injecting a fluid under conditions to perturb therotational flow motion of the solder flux liquid; and impinging thesolder flux liquid upon a mounting substrate for an integrated circuitdie.
 2. The process of claim 1, wherein causing the solder flux liquidto achieve the rotational flow motion is done by rotating the solderflux liquid inlet tube.
 3. The process of claim 1, wherein causing thesolder flux liquid to achieve the rotational flow motion is done byrotating the solder flux liquid inlet tube and to cause a firstperturbation thereof by ejecting the solder flux liquid from the solderflux liquid inlet tube.
 4. The process of claim 1, wherein causing thesolder flux liquid to achieve the rotational flow motion is done byrotating the solder flux liquid inlet tube and to cause a firstperturbation thereof by ejecting the solder flux liquid from thesolder-flux liquid inlet tube, and wherein injecting the fluid underconditions to perturb the rotational flow motion of the solder fluxliquid is a second perturbation thereof.
 5. The process of claim 1,wherein the rotational flow motion is relative to the coaxial fluid-flowcap.
 6. The process of claim 1, wherein causing the solder flux liquidto achieve the rotational flow motion is done by rotating thesolder-flux inlet tube in a first direction, and wherein the coaxialfluid-flow cap is rotated in a second direction.
 7. The process of claim1, wherein injecting the fluid is carried out at an angle that isorthogonal to the solder flux liquid rotational flow motion.
 8. Theprocess of claim 1, wherein the solder flux liquid is injected into thecoaxial fluid-flow cap at a tangent direction to the coaxial fluid-flowcap.
 9. The process of claim 1, wherein the solder flux liquid isinjected into the coaxial fluid-flow cap at a coaxial direction to thecoaxial fluid-flow cap.
 10. A process comprising: injecting a solderflux liquid into a coaxial fluid-flow cap through a solder-flux liquidinlet tube; in the coaxial fluid-flow cap, causing the solder fluxliquid to achieve a rotational flow motion; ejecting the solder-fluxliquid from the solder-flux liquid inlet tube to cause a firstfragmentation thereof; injecting a fluid under conditions to perturb therotational flow motion of the solder flux liquid, and to cause a secondfragmentation thereof; passing the solder-flux liquid through a nozzlein the coaxial fluid-flow cap to cause a third fragmentation thereof;and impinging the solder-flux liquid upon a mounting substrate for anintegrated circuit die.
 11. The process of claim 10, wherein thesubstrate is a mounting substrate, the process further including matinga flip chip integrated circuit die with the mounting substrate at thelocation of the impinged solder-flux liquid.
 12. The process of claim10, wherein the substrate is a mounting substrate, the process furtherincluding: mating a flip-chip integrated circuit die solder bump withthe mounting substrate at the location of the impinged solder-fluxliquid; and reflowing the flip-chip integrated circuit die solder bump.13. A process comprising: injecting a solder flux liquid into a coaxialfluid-flow cap through a solder-flux liquid inlet tube; in the coaxialfluid-flow cap, causing the solder flux liquid to achieve a rotationalflow motion; ejecting the solder-flux liquid from the solder-flux liquidinlet tube to cause primary fragments of the solder-flux liquid;injecting a fluid under conditions to perturb the rotational flow motionof the solder flux liquid, and to cause secondary fragments of theprimary fragments; passing the solder-flux liquid through a nozzle inthe coaxial fluid-flow cap to cause tertiary fragments of the secondaryfragments; and impinging the tertiary fragments upon a bond pad of asubstrate for an integrated circuit die, wherein the tertiary fragmentsimpinge more upon the bond pad than upon a keep-out zone (KOZ) that isadjacent the bond pad.
 14. The process of claim 13, wherein causing thesolder flux liquid to achieve the rotational flow motion is done byrotating the solder flux liquid inlet tube.
 15. The process of claim 13,wherein causing the solder flux liquid to achieve the rotational flowmotion is done by rotating the solder flux liquid inlet tube and tocause a first perturbation thereof by ejecting the solder flux liquidfrom the solder-flux liquid inlet tube, and wherein injecting the fluidunder conditions to perturb the rotational flow motion of the solderflux liquid is a second perturbation thereof.
 16. The process of claim13, wherein the rotational flow motion is relative to the coaxialfluid-flow cap.
 17. The process of claim 13, wherein causing the solderflux liquid to achieve the rotational flow motion is done by rotatingthe solder-flux inlet tube in a first direction, and wherein the coaxialfluid-flow cap is rotated in a second direction.
 18. The process ofclaim 13, wherein injecting the fluid is carried out at an angle that isorthogonal to the solder flux liquid rotational flow motion.
 19. Theprocess of claim 13, wherein the solder flux liquid is injected into thecoaxial fluid-flow cap at a tangent direction to the coaxial fluid-flowcap.
 20. The process of claim 13, wherein the solder flux liquid isinjected into the coaxial fluid-flow cap at a coaxial direction to thecoaxial fluid-flow cap.